The Remedy debugger was the first embedded system level debugger in the world. It offered many features that users take for granted today in the days when having a source level debugger was a luxury. Some of these features include:
It started as an academic research project (originally called Melody for debugging the Harmony Operating System). The results were published in a seminal paper on debugging multiprocessors systems.
The current version of Unison continues to use both gdb and Remedy Debugger.